Such a method is known from the document "IBM Technical Disclosure Bulletin", Vol. 33, No. 9, February 1991.
It is designed firstly for reliable and ordered broadcasting of data shared between replicated modules of a data processing system, with each module constituting a node for processing such data.
In the known method, each node connected to the communications network and receiving a data train recovers the data contained in the train in the order the data was inserted therein by the other nodes during the most recent trip of the data train round the ring. The node then makes up a new data train by eliminating from the data train any data that it itself inserted in the train on its preceding trip round the ring, and by adding new data to the tail end of the train. Thereafter, the node sends the new data train over the network for broadcasting to the other nodes as the train makes a trip round the ring. It should be observed that the train may circulate empty when none of the nodes has any data to broadcast.
In such a data processing system, one or more nodes may be subject to faulty operation or to failure causing them to be disconnected from the network. It is nevertheless essential to ensure that the system continues to operate with those nodes that are still operational, by implementing a fault recovery procedure, particularly if the data train has stopped in a faulty node.